I can recreate this problem with my Captivate if I really work at it, but it doesn't occur under normal usage. I noticed the guy testing the various devices held them very tightly and made full contact with almost his entire hand. Under normal circumstances the palm of my hand does not make contact with the device, only my fingers and the base of my thumb...and I might occasionally lose one bar. However, if I hold the device tightly, making sure that every possible part of my hand makes contact with the device, especially the back bottom portion, then I lose most of my signal over a 5-6 second period.

In my mind, this is still a non-issue. If it happened when a normal grip was employed it would be different.